Defected-core Photonic Crystal Fiber Research Articles

Defected-core photonic crystal fiber magnetic field sensor based on Sagnac interferometer

A high-sensitivity magnetic field sensor based on photonic crystal fiber (PCF) Sagnac interferometer is proposed by finite element method (FEM). The elliptical-hole PCF is injected with water-based magnetic fluid. The fiber core is introduced in an elliptical hole to act as a defected core. The sensitivities are 13.25 and −14.32 nm/Oe at the wavelength of 1750 and 1780 nm, respectively, as the magnetic field H is 100 Oe. The simulation result shows that the sensitivity is extremely high near the wavelength of 1765 nm, because the group birefringence Bg is about zero at that wavelength. The above theory is examined in a different configuration by the transmission mode. The average sensitivities are 0.265, 1.63 and −1.915 nm/Oe, respectively, for the dip wavelength A, B and C as the fiber length is 5 cm. The detecting window is 60Oe. We also demonstrate that the sensitivity can be greatly enhanced by 1–2 orders of magnitude by introducing a defected core.

Multiple defect core photonic crystal fiber with high birefringence induced by squeezed lattice with elliptical holes in soft glass

We present a dual mode, large core highly birefringent photonic crystal fiber with a photonic cladding composed of elliptical holes ordered in a rectangular lattice. The fiber is made of borosilicate glass and has a regular set of elliptical holes with an aspect ratio of 1.27 and a filling factor near 0.5. The group birefringence (G) and effective mode area were measured at 1550nm for the fundamental mode and were found to equal 2×10−4 and 20μm2 respectively. We discuss the influence of structural parameters including the ellipticity of the air holes and the aspect ratio of the rectangular lattice on the birefringence and on the fundamental and second modes of the fiber.

Elliptical defected core photonic crystal fiber with high birefringence and negative flattened dispersion

We propose a novel design of photonic crystal fiber (PCF) using an elliptical air hole in the core as a defected core in order to enhance the performance of modal birefringence and to control the properties of chromatic dispersion at the same time. From the simulation results, it is shown that the proposed fiber has high birefringence up to the order of 10(-2), negative flattened chromatic dispersion in a broad range of wavelengths, and low confinement loss less than that of the single mode fiber. The outstanding advantage of the proposed PCF is that high birefringence, negative flattened dispersion, and low confinement loss can be achieved just by adding a small sized elliptical air hole in the core to the elliptical air hole PCF, especially at the same time.

Ultra-flattened chromatic dispersion controllability using a defected-core photonic crystal fiber with low confinement losses

The present paper describes a novel systematic solution to the problem of controlling the chromatic dispersion and dispersion slope in photonic crystal fibers (PCFs), using a structurally-simple PCF with a defected-core. By adjusting the size of the central air-hole defect we can successfully design an ultra-flattened PCF with low confinement losses, as well as small effective mode area. The design strategy is based on the mutual cancellation between the waveguide and the material dispersions of the PCF, by varying the size of the central defected region in the core. The verification of the ultra-flattened chromatic dispersion property of the proposed PCF is ensured with an accurate full-vector finite element method with anisotropic perfectly matched layers. The ultra-flattened dispersion feature, as well as the low confinement losses and the small effective mode area are the main advantages of the proposed PCF structure, making it suitable as a chromatic dispersion controller dispersion compensator, or as candidate for nonlinear optical applications.